Anorectal melanoma: diagnosis and treatment

Challenges in managing anorectal melanoma, a rare malignancy

INTRODUCTION AND IMPORTANCE

Anorectal melanoma is a rare and aggressive malignancy that can be difficult to diagnose due to its nonspecific presentation.

CASE PRESENTATION

We present a case of a 69-year-old woman who presented with painful defecation, bleeding per rectum, and a mass coming out of her anal opening. The initial differential diagnosis included hemorrhoids, rectal polyp, or a malignant lesion of the rectum. However, histopathological evaluation following transanal excision of the rectal mass revealed mucosal melanoma in the anorectal region. Further investigation showed no evidence of locoregional or distant metastasis.

CLINICAL DISCUSSION

Surgery remains the primary treatment option for anorectal melanoma, but complete resection is often not feasible, leading to high rates of local recurrence and distant metastasis. The incidence of metastatic disease at the time of presentation is high, and a multidisciplinary approach is necessary to manage these patients. Currently, standard systemic therapies used for cutaneous melanoma are the mainstay of treatment for metastatic anorectal melanoma, but there is a need for further research to develop tailored treatment strategies.

CONCLUSION

Our case report highlights the importance of considering anorectal melanoma in the differential diagnosis of patients presenting with anorectal symptoms. It emphasizes the need for a multidisciplinary approach to managing this rare malignancy. Early diagnosis, a multidisciplinary approach, and ongoing research into more effective treatments are crucial for improving outcomes for patients with anorectal melanoma.

Long recurrence-free survival of localized rectal melanoma after abdominoperineal resection in comparison to partial excision and highlighting the place of immunotherapy: A case report

Rectal malignant melanomas (RMM) are remarkably uncommon, the rectal location represents less than one percent of all rectal cancer. Because of its low global survival rate, the surgical strategy is a subject of controversy for attaining a r0 resection. the palliative treatment is also debateable, but recently; radiotherapy and immunotherapy became the preferred treatment and offer the best outcome. to ensure r0 resection, abdominoperineal resection (apr) is considered the main surgical option, but because of its morbidity and functional limitations, local excision techniques such as endoscopic mucosal resection (emr) combined with chemoradiotherapy are being increasingly performed to preserve the quality of life and reduce local recurrence rate. In this report, we evaluate the place that apr still keeps as surgical procedure in comparison to partial excision. we report a case of a 72 years old patient, who presented rectal syndrome with rectorrhagia for 2 months, the diagnosis of localized rectal melanoma was confirmed by endoscopy, magnetic resonance imaging, histological analysis tissue with immunohistochemistry. the procedure strategy was a surgical treatment with apr. After a long recurrence-free survival period, the patient develops local recurrence and immunotherapy-resistant metastasis.

Outcomes After Sphincter-Sparing Local Therapy for Anorectal Melanoma: 1989 to 2020

PURPOSE

The treatment paradigm for patients with anorectal melanoma eligible for sphincter-sparing excision has evolved over time. This study examines outcomes across a 30-year era in this rare disease with poor prognosis.

METHODS AND MATERIALS

This retrospective cohort study included all patients with pelvis-confined anorectal melanoma undergoing sphincter-sparing local excision and adjuvant radiation therapy (RT) at our institution between 1989 and 2020. Patterns of care and predictors of outcome were evaluated.

RESULTS

Of the 108 patients included, 92 (85%) presented with clinically uninvolved nodes. For clinically node-negative patients, the sentinel lymph node biopsy rate increased from 18/43 (42%) before 2008 to 38/49 (78%) subsequently and the use of inguinal nodal RT decreased from 33/35 (94%) before 2003 to 1/57 (2%) subsequently. All clinically node-positive patients treated before 2003 received inguinal nodal RT, whereas no node-positive patient treated subsequently received this treatment. Patients treated before 2016 mostly received biochemotherapy, and those treated since 2017 mostly received immune checkpoint inhibitors. With median follow-up of 32 months, 77 patients (71%) recurred. Three-year actuarial outcomes were 84% local control, 64% nodal control, 38% distant metastasis-free survival, 30% disease-free survival, and 51% melanoma-specific survival. Ostomy-free survival at last follow-up was 95%. Factors contributing to outcome were identified. Outcomes for patients treated in the contemporary era (2017+) were not significantly better than those treated earlier.

CONCLUSIONS

Sphincter-sparing surgery followed by adjuvant RT results in excellent local control and ostomy-free survival for locally resectable anorectal melanoma. Overall oncologic outcomes continue to be poor, reinforcing the need to identify more effective therapies.

Extensive resection improves overall and disease-specific survival in localized anorectal melanoma: A SEER-based study

Background

Anorectal melanoma is a rare tumor with a dismal prognosis. The only promising treatment for anorectal melanoma is surgery, either extensive resection (ER) or local excision (LE). However, the optimal extent of resection is still controversial. The purpose of this study was to investigate whether the survival outcomes of anorectal melanoma at different stages are influenced by the surgical approaches (LE or ER) using the National Institute of Health's Surveillance, Epidemiology, and End Results Program (SEER) database.

Methods

The Surveillance, Epidemiology and End Results (SEER) database was queried to identify patients treated for anorectal melanoma (2000–2018). Overall survival (OS) and disease-specific survival (DSS) outcomes were compared for the two surgical approaches (ER or LE) stratified by stage (localized, regional and distant).

Results

A total of 736 patients were included in the study. Details of previous surgical procedures were available for 548 of the study patients: 360 (65.7%) underwent LE, and 188 (34.3%) underwent ER. In localized cases, 199 underwent LE, and 48 underwent ER. The OS (median 45 vs. 29 months, 5-year rate 41.7% vs. 23.4%) and DSS (median 66 vs. 34 months, 5-year rate 51% vs. 30.7%) of patients undergoing ER were significantly better (p = 0.009 and 0.041, respectively) than those who received LE. Multivariate analysis showed that the type of surgery was an independent prognostic factor for both OS and DSS. Among the regional cases, 89 cases had LE, and 96 cases had ER. Patients with regional disease who underwent ER had no significant differences in OS (23 vs. 21 months; p = 0.866) or DSS (24 vs. 24 months; p = 0. 907) compared to patients who underwent LE. In distant cases, 72 cases had LE, and 44 cases had ER. Patients with metastatic disease who had ER also had similar OS (median 11 vs. 8 months; p = 0.36) and DSS (median 11 vs. 8 months; p = 0.593) to those who underwent LE.

Conclusion

Extensive resection can improve the long-term prognosis of localized anorectal melanoma compared to local excision, but the prognosis of the two surgical techniques is comparable in both regional patients and distant patients.

Effect of surgical treatment for anorectal melanoma: a propensity score-matched analysis of the Surveillance, Epidemiology, and End Results programme data

OBJECTIVE

Anorectal melanoma (AM) is a rare but aggressive tumour with limited information in the existing literature. This study aimed to assess the effect of surgical treatment for AM and predict the prognosis of affected patients.

DESIGN

A retrospective cohort study.

SETTING

Data of patients diagnosed with AM between 1975 and 2016 in the USA were collected from the Surveillance, Epidemiology, and End Results (SEER) database.

PARTICIPANTS

This study enrolled a total of 795 patients with AM from the SEER database and the validation cohort comprised 40 patients with AM enrolled from Chinese institutes.

PRIMARY AND SECONDARY OUTCOME MEASURES

Overall survival (OS) and AM-specific survival (AM-SS).

RESULTS

A total of 795 patients with AM diagnosed between 1975 and 2016 were enrolled in this study. Data over the past four decades showed a trend of increase in incidence rate. A nomogram based on a multivariate Cox regression model was generated to predict AM-SS. The C-index of the nomogram was 0.74 (95% CI 0.71 to 0.77) on internal verification. In the validation cohort, the C-index of the nomogram was 0.72 (95% CI 0.68 to 0.76). The results of propensity score matching (PSM) analysis showed that patients who underwent surgical treatment achieved significant survival (OS: log-rank=17.41, p<0.001; AM-SS: log-rank=14.55, p<0.001). Patients who underwent surgery were stratified into local and extended surgery subgroups. AM-SS and OS were also compared after PSM, but the results were not significantly different between the two surgery subgroups (all p>0.05).

CONCLUSIONS

The nomogram based on the analysis of SEER data showed good performance in predicting OS and AM-SS. Patients with AM can benefit from surgery; however, extensive surgery and appendectomy may not improve AM-SS or OS.

Diagnostic performance of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in anorectal melanoma

To evaluate the diagnostic role of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) in initial staging and restaging of anorectal melanoma. This was a single-institution, retrospective observational study; patients for initial staging and with clinical or radiological suspicion of disease recurrence referred for PET/CT between January 2006 and December 2015 were included in the study. Diagnostic performance of PET/CT was evaluated for baseline staging and disease recurrence. A total of 61 patients who were referred for initial staging were included. PET/CT correctly detected primary lesion in 57 (93.44%) cases, regional nodes in 46 (75.4%) cases, nonregional nodes in 22 (36%) cases, and distant metastases in 25 (41%) cases. The sensitivity (SN); specificity (SP); positive predictive value (PPV); negative predictive value (NPV); and accuracy for primary lesion, regional nodes, nonregional nodes, and distant metastases were 96.6%, 100%, 100%, 50%, and 96.7%; 97.9%, 100%, 100%, 93.3%, and 98.4%; 100%, 100%, 100%, 100%, and 100%; and 100%, 100%, 100%, 100%, and 100%, respectively. A total of 24 patients were included for suspected recurrence/restaging. All the patients were treated previously by surgery, radiotherapy, or chemotherapy. PET/CT detected disease recurrence in 20 (83.3%) patients. Ten patients had recurrence at the primary site, 8 of whom also had distant metastases and 2 had only locoregional metastatic nodes. In the remaining 10 patients, there was no primary site recurrence; however, 2 patients had locoregional nodal and distant metastases and 8 patients had only distant metastases. PET/CT was false negative in 1 patient, which missed liver metastasis. SN, SP, PPV, and NPV of PET/CT was found to be 95%, 100%, 100%, and 75%, respectively, with accuracy of 96%. PET/CT demonstrates overall high diagnostic accuracy in the initial staging and detection of recurrent disease in cases of anorectal melanoma.

Primary melanoma of the anorectal region: clinical and histopathological review of 17 cases. A retrospective cohort study

AIM

The aim of our study was to scrutinize diagnostic and treatment factors that may contribute to the low survival rate from anorectal melanoma while adding 17 more cases to the global research database.

METHOD

We carried out a retrospective analysis of 17 cases of anorectal melanoma treated at a single institution from 2000 to 2020. Data on patient age, sex, complaints, treatment and survival as well as tumour size, resection margins, histological and immunohistochemical features were assessed.

RESULTS

The median age of patients was 72 ± 12.49 (45-92) years. Most of the patients were women (n = 11, 64.71%). Three (17.65%) patients underwent no radical treatment. Of eight patients treated initially with radical surgery (either total mesorectal excision or abdominoperineal resection), six (75%) were found to have positive lymph nodes. Mean survival was 20 ± 23.46 (1-84) months. The average diameter of the resected tumours was 5.43 ± 3.02 cm (1.3-10 cm). Most tumours had epithelioid or spindle cell morphology and were positive for one or more melanocytic markers (S100, HMB-45 or MITF). More than half of the tumours contained no or very little melanin pigment. None of the tumours had significant lymphocytic infiltration. Three tumours showed positivity for keratins (PANCK or CAM5.2) and one tumour showed positivity for C-KIT stain.

CONCLUSION

An aggressive surgical approach may have an effect on survival in most early stages while more advanced disease benefits from a more conservative approach. Attention to sentinel lymph nodes and further systemic research into therapy is required. For now, treatment and diagnostic modalities seem to be inconsistent, requiring further investigation to elucidate common points.

Locally advanced anorectal malignant melanoma in septuagenarian patient treated by laparoscopic abdominoperineal resection: A case report

Introduction

Anorectal malignant melanoma (ARMM) is a rare disease with a poor prognosis. In cases involving locally advanced disease, the treatment strategy is difficult, especially in octogenarian patients, because the prognosis is poor, despite the corresponding decrease or loss of the anal function.

Presentation of case

A 78-year-old woman was admitted to a local hospital with chief complaints of severe anal discomfort due to an egg-sized tumor that was protruding out of the anus and melena. A diagnosis of ARMM was confirmed based on the examination of biopsy specimens and imaging study showed swollen lymph nodes on the dorsal side of the middle rectum and left internal iliac lymph nodes.

Laparoscopic abdominoperineal resection with left lateral lymph node dissection was performed. The examination of the resected specimen revealed two polypoid tumors with a maximum diameter of 38 mm and 14 mm with a metastatic lymph node of 62 mm in the mesorectum. The postoperative course was uneventful. Relapse and local recurrence free survival without any complaints was obtained for more than 12 months.

Discussion

With respect to locoregional disease control, it has been reported that abdominoperineal resection can obtain better control of local disease in comparison to local resection. Laparoscopic surgery is advantageous in its facilitation of an early postoperative recovery for elderly patient.

Conclusion

Laparoscopic abdominoperineal resection may control locoregional disease and improve the patient's QOL with early postoperative recovery. —even in septuagenarian patients—may become a treatment strategy for advanced ARMM.

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Anorectal malignant melanoma is a rare disease with a poor prognosis.

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Surgical procedure for anorectal malignant melanoma is controversial.

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APR may achieve better local control for advanced anorectal malignant melanoma.

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Laparoscopic surgery is advantageous in its facilitation of an early recovery for elderly patient.

Outcomes of Surgical Treatment for Patients with Anorectal Malignant Melanoma; Results of Nine Cases in a Single Institution

Anorectal melanoma (AM) is a rare and aggressive malignancy. Two main types of surgical approach for AM are abdominoperineal resection (APR) and wide local excision (WLE). Nine patients with AM underwent surgical treatment between July 2005 and October 2017 at our institution. Two of the patients were diagnosed with localized stage, four with regional stage, and three with distant stage. Laparoscopic APR was performed in six patients with localized and regional stages, whereas palliative APR and/or WLE were performed in those with distant metastasis. Both patients with localized stage lived without relapse for 6.8 years after surgery. One of the patients with regional stage had no relapse during 3.6 years of follow-up. The other three patients had recurrence and died between 6 and 32 months after surgery. The median overall survival (OS) of the cohort was 14.8 months, and the 5- and 10-year OS were 33.3% and 16.7%, respectively. The tumor at the regional stage could be removed through WLE, but preoperative diagnosis of lymph node metastasis is difficult in patients with AM. Further development of the diagnostic method is expected, and future tasks will be to establish the selection criteria to determine which surgical approach is optimal for this devastating disease.

Amelanotic anorectal malignant melanoma in an ulcerative colitis patient: a rare coincidence or a rare association

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal system, known to be associated with increased risk of carcinogenesis. We report the case of a 55-year-old woman, presenting with symptoms of increased bowel frequency, per rectal bleeding and rectal pain with a background of ulcerative colitis (UC). This was presumptively managed as UC flare, with titration of her medications to control the symptoms. However, a flexible sigmoidoscopy revealed an ulceroproliferative lesion in the rectum, which was identified as an amelanotic anorectal malignant melanoma on immunohistochemistry. No local or distant metastases were noted on radiological imaging. The tumour enlarged progressively and was managed with laparotomy and defunctioning stoma followed by palliative chemotherapy and immunotherapy. This is the first such case reported in literature, highlighting the importance of endoscopic assessment and the need to consider other differential diagnosis in patients with symptoms of IBD flare.

Primary Malignant Melanoma of Anorectum CT Findings: a Single Tertiary Center's Experience

Anorectal melanoma is a rare malignancy with very aggressive course. This case series emphasize the role of imaging, contrast-enhanced computed tomography in evaluating such cases before surgery. CT scan of four patients with pathologically proven primary anorectal malignant melanoma was included. CT findings were analyzed from the picture archiving and communication system for the site of involvement, morphological shape, presence of perirectal and anal infiltration, lymphadenopathy, liver metastasis, and occurrence of bowel obstruction for all the four patients. All the four patients presented as polypoidal mass that caused focal expansion and obscuration of rectal lumen without causing colonic obstruction. Perirectal infiltration was seen in 2/4 patients and involvement of anal canal was seen in 3 patients. Distant metastasis was seen in the liver in three out of four patients. In conclusion, primary anorectal malignant melanoma is a rare, highly aggressive tumor and should be considered in patients with a bulky intraluminal polypoid mass that does not cause colonic obstruction in the anorectal region with large-sized lymphadenopathy.

Incidence and Survival Patterns of Rare Anal Canal Neoplasms Using the Surveillance Epidemiology and End Results Registry

Small cell, neuroendocrine tumors, and melanoma of the anus are rare. Limited data exist on the incidence and management for these rare tumors. A large, prospective, population-based database was used to determine incidence and survival patterns of rare anal neoplasms. The Surveillance, Epidemiology and End Results registry was queried to identify patients diagnosed with anal canal neoplasms. Incidence and survival patterns were evaluated with respect to age, sex, race, histology, stage, and therapy. We identified 7078 cases of anal canal neoplasms: melanoma (n = 149), neuroendocrine (n = 61), and small cell neuroendocrine (n = 26). Squamous cell carcinoma (SCC) (n = 6842) served as the comparison group. Anal melanoma (AM) demonstrated the lowest survival rate at 2.5 per cent. Neuroendocrine tumors (NETs) demonstrated similar survival as SCC (10-year survival for regional disease of 25 and 22.3%, respectively). Ten-year survival of small cell NETs resembled AM (5.3 vs 2.5%). Age 60 years or older, sex, black race, stage, and surgery were independent predictors of survival. This study presents the largest patient series of rare anal neoplasms. NETs of the anal canal demonstrate similar survival patterns to SCC, whereas small cell NETs more closely resemble AM. Accurate histologic diagnosis is vital to determine treatment and surgical management because survival patterns can differ among rare anal neoplasms.

Long-term Oncologic Outcome and Its Relevant Factors in Anal Cancer in Korea: A Nationwide Data Analysis

Purpose

Anal cancer is a rare disease in Korea, and thus survival analyses are limited by small sample sizes. This study used the Korea Central Cancer Registry (KCCR) for a survival analysis and for assessing characteristics of anal cancer in a large sample of Koreans.

Methods

From the KCCR, data on 3,615 patients who were diagnosed and treated for anal cancer from 1993 to 2015 were retrieved. Clinicopathologic variables including age, sex, histological type, and Surveillance Epidemiology and End Results (SEER) stage were reviewed, and a survival analysis was performed according to these variables.

Results

The 5-year relative survival rate improved from 39.7% in 1993–1995 to 66.5% in 2011–2015. Squamous cell carcinoma was the most common and showed the highest survival rate. Males and older patients (≥40 years and ≥70 years) showed poor prognoses.

Conclusion

The survival rate for anal cancer in Korea has improved steadily over time. The characteristics related to survival were the histological type, sex, and age. These statistics will be fundamental for future Korean anal cancer research.

Treatment Strategies and Survival Trends for Anorectal Melanoma: Is it Time for a Change?

BACKGROUND

Immunotherapy advances for the treatment of cutaneous melanoma question its efficacy in treating anorectal mucosal melanoma (ARMM). We aimed to identify the prevalence, current management, and overall survival (OS) for ARMM.

METHODS

Review of patients with ARMM from 2004 to 2015 National Cancer Database. Factors associated with immunotherapy were identified using multivariable logistic regression. The primary outcome was 2- and 5-year OS. Subgroup analysis by treatment type was performed.

RESULTS

A total of 1331 patients were identified with a significant increase in prevalence (2004: 6.99%, 2015: 10.53%). ARMM patients were older, white, on Medicare, and from the South. The most common treatment was surgery (48.77%), followed by surgery + radiation (11.75%), surgery + immunotherapy (8.68%), and surgery + chemotherapy (8.68%). 16.93% of patients received immunotherapy, with utilization increasing (7.24%: 2004, 21.27%: 2015, p < 0.001). Patients who received immunotherapy had a significantly better 2-year OS (42.47% vs. 49.21%, p < 0.001), and other therapies did not reveal a significant difference. Adjusted analysis showed no difference in 2- and 5-year OS based on therapy type.

CONCLUSION

The prevalence of ARMM has increased. The use of immunotherapy has increased substantially. Some survival benefit with the administration of immunotherapy may exist that has yet to be revealed. A more aggressive treatment paradigm is warranted.

Primary Dedifferentiated Amelanotic Anorectal Melanoma: Report of a Rare Case

Anorectal melanoma (ARM) is an uncommon aggressive malignancy that comprises 0.5% to 1.6% of all melanoma manifestations. Dedifferentiated melanoma is very rare with loss of all melanocytic differentiation markers and is usually seen in metastatic melanoma of cutaneous origin. In this article, we report the first case of primary dedifferentiated amelanotic ARM in a 68-year-old male who presented with anal discomfort that was initially treated as inflamed hemorrhoids. Physical examination revealed a large protruding anal mass, biopsy of which showed biphasic malignant tumor cells with distinct immunoprofiles: a superficial spindled/sarcomatoid component positive for SOX10 and S100, and a deeper epithelioid/rhabdoid component positive for desmin, AE1/AE3, and EMA. Both components were negative for HMB-45, Melan-A/MART-1, c-Kit, and other lineage markers. Molecular analysis by polymerase chain reaction demonstrated wild-type BRAF and KRAS genes. A diagnosis of dedifferentiated ARM was made based on the coexistence of a differentiated component (spindled: S100 and SOX10 positive) and a dedifferentiated component (epithelioid: all melanoma markers including S100 and SOX10 negative). Shortly afterwards, the patient developed extensive pulmonary and liver metastases and expired 20 days after the diagnosis was rendered, reinforcing the highly aggressive nature of this disease entity.

Multiple synchronous anorectal melanomas with different colors: A case report

BACKGROUND

Anorectal melanoma (AM) is an extremely rare malignant tumor originating from anorectal melanocytes with a poor prognosis. AM has been reported to have a much lower incidence than cutaneous or choroid melanoma, accounting for 0.4%-1.6% of all melanomas.

CASE SUMMARY

We report a 76-year-old female patient diagnosed with anorectal malignant melanoma by colonoscopy and biopsy. Intraoperative examination revealed two distinct anorectal tumors, one melanotic and another amelanotic, as well as two pigmented mucosal zones at the dentate line level. Abdominal perineal resection was performed. A pathological report confirmed all four lesions to be melanomas. Postoperatively, we followed an immunotherapy protocol targeting PD-1 (nivolumab). The patient had 24 mo of disease-free follow-up upon completion of nivolumab treatment.

CONCLUSION

This is the first reported case presenting coexistence of pigmented and unpigmented AMs in the same patient.

Primary anorectal melanoma: clinical, immunohistology and DNA analysis of 43 cases

Primary melanoma involving the anorectal region is rare, accounting for <1% of all melanomas in most Western countries. It characteristically presents at an advanced clinical stage and is associated with poor clinical outcomes. Preliminary reports suggest that response rates to immunotherapies in patients with advanced stage mucosal melanoma are much lower than in cutaneous (or acral) melanoma patients but reasons for this are unclear. Comprehensive characterisation of the immune microenvironment in anorectal melanoma has not previously been performed. A single-institution cohort of 43 primary anorectal melanoma patients was examined to describe clinicopathological features and characterise the immune microenvironment to provide insights into the behaviour of this rare melanoma subtype. The tumours displayed multiple adverse prognostic attributes including deep thickness (median 11.5 mm), ulceration (81%) and high mitotic rate (median 12/mm²). The median overall survival was 24 months and the median recurrence-free survival was 9 months. Tumour-infiltrating lymphocytes (TILs) were absent or mild in most tumours (75%); PD-L1 positive staining (>1% of tumour cells) was present in 44% of cases, however in 86% of positive tumours the percentage of positive cells was ≤10%. Four tumours underwent whole genome sequencing; no ultraviolet signature was identified, and there was a lower mutational load but higher structural chromosomal variant load compared with cutaneous melanomas. Poor responses of anorectal melanomas to immunotherapy may be caused by lower immunogenicity of these tumours as characterised by low mutation burden (and therefore low neoantigenicity), low TILs infiltrates and low PD-L1 expression. Further investigation is required to determine whether TILs and PD-L1 expression predict response to immunotherapy in patients with mucosal melanoma.

Anorectal melanoma treated with abdominoperineal resection

The diagnosis of primary malignant melanoma of the anorectum is extremely rare and carries a very poor prognosis. While it is the third most common site of a primary melanoma, it accounts for <1% of anorectal malignancies. We present cases of anorectal melanoma treated with abdominoperineal resection.

JOURNAL CLUB: Primary Anorectal Melanoma: MRI Findings and Clinicopathologic Correlations

OBJECTIVE

The purpose of this study is to evaluate the MRI features of primary anorectal malignant melanoma and to correlate these features with its clinical and pathologic characteristics.

MATERIALS AND METHODS

The medical records of 12 patients (five men and seven women; mean age [± SD], 60.8 ± 10.0 years) with pathologically proven primary anorectal melanoma were retrospectively reviewed. MRI findings were analyzed to determine the shape, size, distance from the anal verge, presence of perirectal or anal infiltration, signal intensity on T1- and T2-weighted images, presence of diffusion restriction, contrast enhancement pattern of the lesion, presence of lymphadenopathy, and occurrence of bowel obstruction. Subsequent follow-up data for the patients were recorded.

RESULTS

The most common presentation was hematochezia (41.7% of patients). Common findings on MRI included a large intraluminal polypoid mass (75.0% of lesions) with little perirectal or anal infiltration (100.0%), T1 hyperintensity (66.7%), high T2 signal intensity (54.5%) or mixed T2 signal intensity (45.5%), restricted diffusion (100.0%), and hyper-enhancement (100.0%). The mean length, width, and depth of these masses were 3.5, 2.9, and 2.3 cm, respectively. The mean distance from the anal verge was 1.8 cm. Lymphadenopathy was frequently identified (75.0% of cases), with lymph nodes larger than 2 cm noted in 28.5% of cases and most commonly involving the perirectal area (77.8% of cases). No colonic obstructions were observed. The mean patient follow-up was 32.7 months. A total of 25.0% of patients died as a result of disease progression.

CONCLUSION

The possibility of the presence of anorectal melanoma should be considered for patients with a bulky intraluminal polypoid mass in the anorectum without colonic obstruction, with the mass showing T1 hyperintensity, high or mixed signal T2 intensity, hyperenhancement, minimal perirectal or anal infiltration, and lymphadenopathy.

Endoscopic diagnosis of primary anorectal melanoma

OBJECTIVE

The present study retrospectively analyzed case data from 12 patients diagnosed with anorectal melanoma, with the purpose of identifying key diagnostic features at endoscopy.

MATERIALS AND METHODS

Images from colonoscopy were reviewed for all patients in order to establish the endoscopic features of primary anorectal melanoma. For the patients whose colonoscopic examinations included endoscopic ultrasound, images were examined to characterize lesions and the depth of infiltration, the results of which were compared with pathological findings after operative resection.

RESULTS

At colonoscopy, superficial melanin pigmentation was identified in 10 patients with anorectal melanoma, with morphology including spots, patches, or sheets of pigmentation. In patients who underwent endoscopic ultrasound, lesions appeared as masses on the mucosal side with inhomogeneous or low-level internal echoes or ulcer-type lesions invading the muscularis propria. Lesions diagnosed as anorectal melanoma also demonstrated irregular margins and varying degrees of submucosal infiltration. Infiltration depth of melanoma via endoscopic ultrasound (EUS) was concordant with surgical pathology results in 100% of patients.

CONCLUSION

Colonoscopy combined with biopsy and subsequent pathological examination can accurately diagnose primary anorectal melanoma. Moreover, EUS is a reliable tool for assessing the depth of infiltration of this disease.

Anorectal mucosal melanoma

Anorectal melanoma is an uncommon and aggressive mucosal melanocytic malignancy. Due to its rarity, the pre-operative diagnosis remains difficult. The first symptoms are non-specific such as anal bleeding, anal mass or pain. Although anorectal melanoma carries a poor prognosis; optimal therapeutics strategies are unclear. Surgical resection remains the mainstay of treatment. The optimal surgical procedure for primary tumours is controversial and can vary from wide local excision or endoscopic mucosal resection (EMR) to an abdomino-perineal resection. A high degree of uncertainly exists regarding the benefit of radiation therapy or chemotherapy. The treatment of advanced melanoma is evolving rapidly with better understanding of the disease biology and immunology. Considerable effort has been devoted to the identification of molecular determinants of response to target therapies and immunotherapy.

Anal Melanoma in an Elderly Woman Masquerading as Hemorrhoid

Anal melanoma is a rare and aggressive neoplasm of the anal canal seen in the elderly population in the six or seventh decade of their lives. Presentation is usually nonspecific and diagnosis is often delayed or missed initially. The management is surgical and prognosis is poor. Here we present a case of anal melanoma in an elderly patient masquerading as hemorrhoid.

Extensive surgery and lymphadenectomy do not improve survival in primary melanoma of the anorectum: results from analysis of a large database (SEER)

AIM

Primary anorectal melanoma is a rare disease with a dismal prognosis due to early distant metastasis. The prognostic value of positive loco-regional lymph nodes and the impact of lymphadenectomy on overall survival are unclear. We have investigated this by analysis of data obtained from a national representative database, controlling for potential confounders.

METHODS

Data were retrieved from the Surveillance, Epidemiology and End Results (SEER) database. Multiple imputation analysis was performed to deal with missing data. Cox regression models were formulated using different prognostic factors including site of origin, gender, size, race, rate of lymph node metastasis (ratio between positive lymph node count and total lymph nodes harvested), extent of lymphadenectomy (none, level I etc.), age, type of surgery, stage of disease and administration of radiotherapy.

RESULTS

Our population was composed of 208 patients who underwent surgery between 1998 and 2012. Rate of lymph node metastasis (P = 0.027; hazard ratio 1.873, 95% CI 1.076-3.261) and race (P = 0.019; hazard ratio 2.291, 95% CI 1.148-4.575) were found to be independent predictors of survival.

CONCLUSION

Based on the data retrieved from the SEER database, metastasis to loco-regional lymph nodes is an important prognostic factor, but lymphadenectomy does not improve survival.

Incidence, Surgical Treatment, and Prognosis of Anorectal Melanoma From 1973 to 2011: A Population-Based SEER Analysis

Anorectal melanoma (AM) is a rare type of melanoma that accounts for 0.4% to 1.6% of total malignant melanomas. The incidence of AM increases over time, and it remains highly lethal, with a 5-year survival rate of 6% to 22%. Considering the rare nature of this disease, most studies on AM comprise isolated case reports and single-center trials, which could not provide comprehensive assessment of the disease. Therefore, we conducted a population-based study by using the Surveillance, Epidemiology, and End Results (SEER) program to provide the latest and best available evidence of AM.We extracted all cases of AM registered in the SEER database from 1973 to 2011 (April 2014 release) and calculated age-adjusted incidence. Only cases with active follow-up were included to predict factors associated with prognosis. Survival outcomes were also compared among different types of surgery.We identified 640 AM cases, which consisted of 265 rectal melanoma and 375 anal melanoma. The estimated annual incidence rates of AM per 1 million population were 0.259 in males and 0.407 in females, and it increased with advanced age and over time. Tumor stage and surgical treatment were independent predictors of survival. Results implied that surgery improved the prognosis of patients with local- and regional-stage AM but could not prolong the survival of patients with distant-stage AM. Moreover, the outcome of less extensive excision was not statistically different from that of more extensive excision.This study provides an up-to-date estimation of the incidence and prognosis of AM by using SEER data. The incidence of AM continuously increases over time, despite its rarity. This disease also exhibits poor prognosis. Thus, AM must be further investigated in future studies. We also recommend surgery as the optimal treatment for local- and regional-stage AM patients but not for those with distant metastasis.

Anorectal malignant melanoma: retrospective analysis of management and outcome in a single Portuguese Institution

Anorectal melanoma is an uncommon cancer with a poor prognosis. We aim to describe the clinical presentation, treatment and outcome of patients with anorectal melanoma in our center. Retrospective study of patients with anorectal melanoma treated between 2000 and 2011 at a cancer center in Lisbon. Ten patients were identified, eight females and two males, with median age 70.5 years (32-79). Symptoms at presentation were rectal bleeding (8), anal pain (4) and discomfort (3). Tumor location was anal (6), rectal (3) and anorectal transition (2). Seven patients had surgery: abdomino-pelvic resection (5) and local resection (2). Among the two patients who underwent local resection, one was an incidental finding in a hemorrhoidectomy specimen. This patient had further adjuvant chemotherapy (dacarbazine). Three patients had distant metastasis at diagnosis, one had chemotherapy and two had best supportive care. Six of the seven operated patients relapsed in a median time of 5.4 months: distant metastasis (4), local recurrence (1), both (1). The two local relapse patients had surgical widening of resection margins (1) and radiotherapy (2). One-year survival was 30 %; 3-year survival was 20 %. Anorectal melanoma has a poor prognosis due to advanced disease at presentation and aggressive course, with relapse in almost all operated patients. Treatment guidelines have not been established due to the lack of randomized studies. However, recent studies show that sphincter-sparing surgical procedures along with low dose intensity radiotherapy seem to achieve a local control similar to abdomino-pelvic resection. No systemic therapy is considered standard of care for advanced disease, and regimens are extrapolated from cutaneous melanoma experience.

Unexpected post-operative diagnosis of primary rectal melanoma. A case report

AIM

Anorectal melanoma (ARM) is a very uncommon and highly lethal malignancy. Due to its rarity and non-specific symptoms, preoperative diagnosis may be often erroneous and subsequent treatment inappropriate. We report a case of primary rectal melanoma and discuss the current diagnostic and therapeutic challenges.

CASE REPORT

An 87-year-old man was admitted to our surgical unit with a history of progressive constipation, tenesmus, rectal bleeding and transanal mucous discharge. Preoperative investigations, including CT scan and colonoscopy with biopsy, were suggestive for locally advanced low rectal sarcoma and therefore the patient underwent abdominoperineal resection (APR). However, histopathological examination and immunohistochemistry resulted in a postoperative diagnosis of primary rectal melanoma. The patient died 6 months later due to local and systemic recurrence.

CONCLUSION

ARM should always be considered when unusual anorectal lesions are discovered. Regardless of the pathological stage and the extent of surgery, prognosis of ARM remains poor. Thus, whenever feasible, wide local excision is now the preferred treatment, since it is associated with lower postoperative morbidity and better quality of life compared to APR. In our case, although the initial diagnosis was incorrect, APR was justified by the local invasiveness and large size of the tumor.

Characteristics and survival of korean anal cancer from the Korea central cancer registry data

Purpose

In Korea, anal cancer is rare disease entity with specific clinical characteristics. Therefore, no survival analysis with a sufficient patient population has been performed. The aim of this study was to evaluate the characteristics of Korean anal cancer, focusing on the survival according to tumor histologies, sex, and a specific age group, using the nationwide cancer registry.

Methods

Using the Korea Central Cancer Registry, we analyzed a total of 2,552 cases from 1993 to 2010. We assessed the 5-year relative survival by using tumor histology. In addition, survival differences of Surveillance Epidemiology and End Results (SEER) stage were analyzed for both sexes and for young-age cancer (younger than 40 years) and advanced-age cancer (older than 70 years).

Results

The 5-year relative survival among anal cancer patients increased from 38.9% for the period 1993-1995 to 65.6% for the period 2006-2010. The anal squamous cell carcinoma was the most common histology and showed better survival than other types of cancer. Females demonstrated better survival than males in all SEER stages. The 5-year survivals for patients in whom anal cancer developed before the age of 40 and at or after the age of 40 were 62.4% and 51.6%, respectively. The 5-year survival for patients in whom cancer developed at or after the age of 70 was much worse than that for patients in whom the cancer had developed prior to that age.

Conclusion

Korean anal cancer has certain distinctive characteristics of survival according to tumor histology, sex, and age. Despite limitations on available data, this study used the nationwide database to provide important information on the survival of Korean patients with anal cancer.

Endobronchial metastasis from primary anorectal melanoma

Patient: Male, 64

Final Diagnosis: Metastatic anorectal melanoma with endotracheal metastasis

Symptoms: Fatigue • weight loss • hematochezia • cough

Medication: None

Clinical Procedure: Biopsy of anal mass • rigid bronchoscopy

Specialty: Internal medicine • oncology • pulmonology

Laparoscopic abdomino-perineal resection for patients with anorectal malignant melanoma: a report of 4 cases

Anorectal malignant melanoma is a very rare but lethal disease. Patients with anorectal malignant melanoma commonly complain for changes in bowel habits and rectal bleeding. Therefore, anorectal malignant melanoma is often misdiagnosed as hemorrhoids, polyp or rectal cancer. Surgery is the mainstay of treatment for patients with anorectal malignant melanoma. However, whether abdominoperineal resection or wide local excision is the most appropriate surgical approach is still a controversial issue. Recently, with the great development of laparoscopic techniques, more and more operations can be performed by laparoscopic techniques. However, laparoscopic abdominoperineal resection for management of anorectal malignant melanoma has been rarely reported. In this study, we reported 4 patients with anorectal malignant melanoma underwent laparoscopic abdominoperineal resection. The outcomes of these patients were relatively good during a long time follow-up. Meanwhile, we reviewed the relevant studies with particular focus surgical treatment.

Anal versus rectal melanoma: does site of origin predict outcome?

BACKGROUND

Anatomic site is a predictive factor in subtypes of cutaneous and mucosal melanoma.

OBJECTIVE

The aim of this study was to examine the clinical relevance of location of origin of anorectal melanoma as a prognostic factor.

DESIGN

With the use of a prospectively maintained database, clinical characteristics, management, and outcomes were compared according to the site of origin. SETTINGS, PATIENTS, INTERVENTIONS: A retrospective review was conducted of patients diagnosed with anorectal melanoma from 1994 to 2010. Tumors were defined as anal, anorectal, or rectal melanoma according to their anatomic relationship to the dentate line.

MAIN OUTCOME MEASURES

Clinicopathologic factors were compared by χ2 test. Time-to-event analysis was performed by Kaplan-Meier analysis.

RESULTS

Of the 96 patients included (41 with anal melanoma, 32 with anorectal melanoma, 23 with rectal melanoma), patients with rectal and anorectal mucosal melanoma had advanced primary tumors (median Breslow thickness, 12 mm and 8 mm, p = 0.002), whereas anal lesions could be found at earlier depths (median thickness, 6.5 mm). Patients with anal tumors more commonly underwent transanal excision (p < 0.02) and sentinel lymph node biopsy (p = 0.004) versus anorectal and rectal tumors. Patterns of recurrence were also distinct; nearly two-thirds of anorectal and rectal tumors recurred systemically, whereas anal melanoma more often recurred within the lymph nodes first (63%; p < 0.02). Recurrence occurred in 24 (59%) patients with anal tumors, 23 (72%) patients with anorectal tumors, and 16 (70%) patients with rectal tumors. Median overall survival was 22 months for anal melanoma, 28 months for anorectal melanoma, and 27 months for rectal melanoma. Recurrence and survival were not statistically different between the groups.

LIMITATIONS

This study is limited by small sample size and its retrospective nature.

CONCLUSIONS

This study represents the only series describing the outcomes of anorectal melanoma by anatomic location. Lesions at or proximal to the dentate line present with more advanced disease, possibly related to a delay in diagnosis. Lesions distal to the dentate line more commonly recur within lymph nodes, which may represent differences in nodal drainage. Irrespective of location, the long-term prognosis remains poor for all cases of anorectal melanoma.